Dental handpiece



United States Patent DENTAL HANDPIECE Charles A. Ellis, Rochester, N.Y.,assgnor to Ritter Company, Inc., Rochester, N.Y., a corporation ofDelaware Application January 9, 1958, SerialNo. 707,964

3 Claims. (Cl. 32--27) This invention relates to dental handpieces,andmore particularly to a dental handpiece having an adjustable head,one object being the provision ofk a moresatisfactory handpiece of thisnature.

Dental handpieces generally comprisea cylindrical body portion adapted:to be held by the dentist, a means for holding ayburr or other dentaltool, and meansfor imparting-rotary motion to the dentaltool. In thecase of. handpieces having self-contained source of power such as theair turbine driven handpiece described in the.y Charles A. Ellisapplication for patent on Dental Handpiece Drive Mechanism, Serial No.680,454, led August27, 1957, the air driven turbine or other source ofpower is con: tained within the grip portion of the handpiece andtransfers rotary motion directly to the tool. However, ithas been foundythat it is often desirable to adjust theangle between the grippingportion of the handpiece,A andv the tool so as to enable the operator toconveniently Work on certain portions of the patients teeth. It istherefore desirable to have a dental handpiece containingaprovision forvarying the angle between the gripping.v portion and the tool and theprovision of such a. handpiece, is an object of this invention.

Provision of a handpiece having means forvaryingthe angle of thegripping portion and the-tool must contain a provision for thetransmission of power through this varying angle and the provision ofsuch transmission means is another object; of this invention. Otherobjects of this invention include the provision of a dental handpiece ofthe above description which'is relatively simple, Positive in operationand easy to maintain.

Other objects and advantages of my inventiorrzwill be particularly setforth in the claims and will be apparent from the following description,when taken in connection with the accompanying drawings, in which:

Fig. 1 is a bottom plan view of a dental handpiece embodying thisinvention;

Fig. 2 is a cross-sectional View of the handpiece of Fig. 1 takensubstantially along lines 2-2 in the direction of the arrows;

Fig. 3 is a cross-sectional view taken substantially along lines 3 3 ofFig. 1 in the direction of the arrows;

Fig. 4 is a cross-sectional view taken substantially along lines 4 4 ofFig. 2 in the direction of the arrows; and

Fig. 5 is a fragmentary side elevational View, partially cut away, of adental handpiece embodying this invention.

A dental handpiece embodying the present invention for the reception ofa dental tool, and transmission means for transferring the rotary motionof said turbine means -to said ltool holding means.

Referring now to the drawings, 10 is a casing which is :shown as beingof substantially cylindrical shape but which 2, may be tapered andserrated as: i`s Well, known inthe art for providing a convenient and'.comfortable gripping surface. A block 1-2 (Fig. 2.)A containing,theturbine. drive elements. is mounted in casing 10. Block. 12 containsa cavity 14-which is adapted toM contain a turbine. rotor 16 on a shaft17 rotatably mounted in bearingsv 18- in line with the longitudinal axisof casing10'. Suitable passageways 20 and 22 are provided in block 12for the ow of air to and from turbine rotor. 16. An` air line4 24whichcommunicates with.A a. suitable source of. compressed air (not shown) isconnected to-passage. 20 for providinga source of air to drive. turbine,16. An eccentric stud. 24 is mounted on and extends forwardly from thefrontend of shaft 17 of turbine 16 for. purposes hereinafter to bedescribed. StudZA ispreferably. an. integral part of shaft 17, but itmay be separately madeand fastenedl tothe shaft.

A removable inner casing-2.6 (Fig,` 2) is inserted in the fore part ofcasing 10. Casing 26'contains. mechanism hereinafter described, fortransmittingthe motion of turbine 16to. a dental burr. orother tool..Casing26 and its. associated mechanism is. removable from outer casing10 as a unit, so thatvarious transmission means and head mechanism may.besubstitutedfor the one to.. be shown. I

The power transmission mechanism in casing 26 comprises an internallytoothedcringgear 28. mounted on the interior surface of the casingas`shownin Fig. 2, meshing with a pinion gear 30. GearA 30.is. bored. toreceive a bearing32. on stud.24. A4v forwardly extending shaft.34 formsanintegral part ofpiniongear. 30. The forward end of shaft. 34 is.supported in. a. ball bearing36.(Fig..2) mounted on the interior.- of.afplugSSr-which. closesthe forward end of inner. case.26. Whenrturbinelrotates, eccentric stud24 movespinion gear tlinacircular path, andpinion 30` rolls aroundfon. the interior teeth of xed ring gear` 28,thus imparting,thecombinationvof.a rotary and a rocking motiontoshaft34. Bearing 36 is-loose enough to. rotationally` supportA shaftk34k and Vallow this limited rocking motion. A pinion gear35is mountedonthe frontend of shaft 34. Pinion gear. 35T may either be formedgas anintegral parttof. shaftv 34,-or itmay be separately made and fastened. Ito the1shaft, if desired.

The. casing holdingthe dental tool comprises a sube stantiallycylindricalshell. mounted on. a saddle-'shaped block .38. Block38.carries apair.of.outwardlyextending threaded trunnions or studs 40which engage a pair of forwardly extending triangular shaped ears 42(Figs. 1 and 5) forming integral portions of casing 10. Ears 42 areclamped against block 38 by means of a pair of ad justing nuts 44threadedly engaging studs 40. The outer surface of block 38 and theinner surfaces of ears 42 may be serrated in a circular pattern asindicated at 46 in Fig. 5, so that when nuts 44 are drawn tight to forceears 42 against block 46, the latter parts are `securely locked againstrotation.

A shaft 4S is mounted in casing or shell 36 on a pair of bearings 5t)and 52 as shown in Fig. 2. The lower end of shaft 48 contains a taperedhole 54 for the reception of the shank of a burr or other dental -tool56. A crown gear 53 is rigidly mounted on shaft 48 with its teeth inengagement with gear 35 on the end of shaft 34. Thus, rotary motion istransferred from shaft 34 through gear 35 to gear 5S, which in turncauses rotation of shaft 48, driving dental tool 56.

It will be appreciated that since eccentric 24 imparts a rocking motionto gear 30, gear 35 will also have a limited rocking as well as a rotarymotion. However, since bearing 36 is relatively nearer to gear 35 thanit is to gear 30, this rocking motion of gear 35 will be relativelysmall. Suiicient clearance is allowed between the teeth and gear 35 andcrown' gear 58 so that this rocking motion does not interfere with thefunctioning of these parts. In any case, since shaft 48 is held bybearings 50 and 52, the rocking motion of shaft 34 does not interferewith the alignment thereof. l

Studs 40 on block 38 are carefully positioned so that they are in linewith the pitch line of crown gear 58. Thus, when casing 36 is adjustedby rotating the same about studs 40, the relation between gears 35 and58 is not disturbed. The edges of the teeth of crown gear 58 areslightly beveled so that the change in angle between gear 58 and gear 35does not interfere with the transmission of power between these twogears. Thus, the rotary motion imparted to shaft 34vby means ofeccentric 2'4 is transmitted through gear 35 to crown gear 58irrespective of the angle at which shaft 4S is adjusted with respect tocasing 10. For this reason, angle of dental tool 56 may be adjustedrelative to casing 10 so that the dentist may work at the mostconvenient angle for the job being carried out.

, It will be appreciated that under certain circumstances, that thedentist may wish to have a straight handpiece, that is, a handpiecehaving the tool substantially in line with the axis of casing 10. Shouldthis be the case, inner casing 26 may be simply slid out of casing 10and a new casing 26 having a different type of tool supporting headattached thereto may be substituted. Further, should gears 28 or 30,crown gear 58, or pinion 35 wear, or otherwise become inoperative, andrequire adjustment or replacement, this can be most convenientlyaccomplisbed by sliding inner casing 26 out of outer casing 10, andsubstituting an entirely new assembly consisting of a new casing 26 andassociated parts, while the old casing 26 with its associated parts maybe returned to the factory for repair or adjustment as desired. Thus,the removability of casing 26, which carries all the operative partsofthe dental handpiece with the exception of the turbine, allows theremoval of these parts for adjustment or repair, or replacement, and atthe same time allows a different type of tool supporting mechanism to besubstituted for the one shown. This greatly increases the exibility ofthe tool herein described, as well as greatly simplifying themaintenance and replacement of the `operative parts.

Thus, it will be seen that this invention carries out its statedobjects. The dental handpiece herein disclosed shows a self-containedhandpiece which is adjustable within limits in order to provide the mostconvenient angle between the hand held instrument and the dental tool sothat the dentist may conveniently work on any y 4 part of the patientsteeth. It is simple and rugged in construction, and so designed that thechange in angle between the bore and the handpiece does not effect theinternal power transmitting parts.

While there has been shown and described the preferred forms ofmechanisms of the invention, it will be apparent that various changesand modiiications may be made therein, particularly in the form Iandrelation of parts, without departing from the spirit of the invention asset forth in the appended claims.

I claim:

l. A dental handpiece comprising, in combination, an elongated bodyportion, a turbine element mounted in said body portion for rotationabout an axis substantially parallel to the longitudinal axis of saidbody portion, an eccentric element mounted on said turbine element, gearmeans rotatably mounted on said eccentric element, internally toothedgear means fixed to said body portion engaging said rotatably mountedgear means, a shaft having one end attached to said rotatably mountedgear means, second gear means mounted on the other end of said shaft, adriven shaft, gear means on said driven shaft meshing with said secondgear means, and means on said driven shaft for gripping a dental tool.

2. A dental handpiece comprising, in combination, an elongated bodyportion, a turbine element mounted in said body portion for rotationabout` an axis substantially parallel to the longitudinal axis of saidbody portion, an eccentric element mounted on said turbine element, agear rotatably mounted on said eccentric element, an internal` gearmeans xed to said body portion and engaging said rotatably mounted gearmeans, a shaft having one end attached to said rotatably mounted gearmeans, second gear means mounted on the other end of said shaft,trunnion means engaging said body portion, a housing mounted on saidtrunnion means for limited rocking motion, a driven shaft in saidhousing, and crown gear means on said driven shaft for engaging saidsecond gear means, with the pitch line of said crown gear means lyingsubstantially on the axis of said trunnion means.

3.y A dental handpiece claimed in claim 2 and including means forlocking said housing in adjusted position.

Case et al Mar. 8, 1898 Iseman July 29. 1941

